Question: $ { {-3} \times \left[\begin{array}{rr}{4} & {0} \\ {-2} & {4}\end{array}\right] = {?} } $
To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{rr}{-3}\times{4} & {-3}\times{0} \\ {-3}\times{-2} & {-3}\times{4}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{-12} & {0} \\ {6} & {-12}\end{array}\right]}$